Illumination device

ABSTRACT

An Illumination device includes light emitting devices and an optical system for collimating light emitted by the light emitting devices. A first group of the light emitting devices are arranged in a first array having first gaps, and a first optical system is arranged near the first group of light emitting devices. At least one second group of the light emitting devices are arranged in a second array, and the second array has second gaps. The second optical system is arranged near the second group of light emitting devices. The first and second optical systems are arranged so that, in a distance from the illumination device, light emitted by the first group of light emitting devices, collimated by the first optical system, and light emitted by the second group of light emitting devices, collimated by the second optical system, are superimposed to form a gap-free illumination field.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 17/681,465, filed on Feb. 25, 2022, which is a continuation ofthe International Application No. PCT/EP2020/074021 filed Aug. 27, 2020,which claims priority to and the benefit of European Patent ApplicationNo. 19193848.9, filed on Aug. 27, 2019. The aforementioned applicationsof which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to illumination devices. Morespecifically, the present disclosure relates to illumination devicesincluding a plurality of LED light source devices.

BACKGROUND

LED based illumination devices have replaced conventional light sourcedevices, e.g., incandescent light source devices, in many applications.Low energy consumption, long lifetime, and high variability in color andcolor temperature make LED based illumination devices a preferred choicefor most applications.

For technical reasons, LED based illumination devices usually include aplurality of individual light emitting devices, each including an LEDlight source device. The plurality of individual light emitting devicesare commonly arranged in arrays, e.g., linear arrays.

In some applications, directional illumination is required. Fordirectional illumination, light emitted by the plurality of lightemitting devices is collimated by optical systems, such that the lightfrom each of the light emitting devices is shaped into a light beam witha narrow cone angle. A possible cone angle of a light beam can be 2°.

LED light source devices used in illumination devices usually include anLED chip for emitting excitation light, and a phosphor body covering theLED chip for converting excitation light into illumination light of apredetermined color temperature. As LED chips emit light within a narrowwavelength bandwidth, such light may not be well suited for illuminationpurposes. Therefore, phosphors are used to convert some or all of thelight emitted by the LED chip into illumination light of a predeterminedcolor temperature. Color temperature can be determined based on specificapplication of an illumination device.

When a plurality of LED light source devices are placed in closeproximity to each other, excitation light of one LED chip can travelinto the phosphor body of a neighboring LED light source device. Thismay affect contrast available by selectively activating or deactivatingindividual LED light sources. In order to achieve a desirable contrast,e.g., about 200:1 or higher, known LED light sources therefore furtherinclude a light blocking layer on the lateral surfaces of the LED chipand/or the phosphor body. The light blocking layer may include siliconmixed with titanium dioxide particles. The light blocking layer issometimes also referred to as side coating.

Due to the light blocking layers, arrays of LED light sources alwaysinclude dark surface portions interposed between light emitting surfaceportions, irrespective of how tight the individual LED light sources arepacked in the array. Due to further technical constraints, e.g.,handling of individual LED light sources during manufacturing, LED lightsources may be packed in an array with gaps. Packing LED light sourcesin an array with a reduced gap may be related to heat management. Whenlight emitted by an array of LED light sources, which includes darksurface portions interposed between light emitting surface portions, iscollimated by an optical system, the resulting illumination field has acomb-like structure with individual beams, emanating from the individualLED light sources, separated by gaps. Such illumination fields can bedisadvantageous, e.g., when used for illumination of a road by vehicleheadlights or streetlights, or for illumination of a workspace by a roomlight.

The gaps in the illumination field can be reduced or even completelyremoved by modification of the optical system for collimation of thelight. However, such modifications may increase complexity of theoptical system and cost of the illumination device.

SUMMARY

In view of above, it is desirable to have an illumination deviceincluding a plurality of LED light source devices arranged in an array,which provides for a light field with improved homogeneity.

It is desirable to have an illumination device including a plurality ofLED light source devices arranged in an array, and with an opticalsystem of reduced complexity.

It is also desirable to have an illumination device including aplurality of LED light source devices arranged in an array, whichprovides for improved heat management.

Some or all of the above objectives are achieved by illumination devicesaccording to the appending claims.

In one or more embodiments according to the present disclosure, anillumination device is provided with a plurality of light emittingdevices and an optical system for collimating light emitted by theplurality of light emitting devices. Each of the light emitting devicesincludes an LED light source device having an LED chip for emittingexcitation light, a phosphor body covering the LED chip for convertingexcitation light into illumination light of a predetermined colortemperature, and a light blocking layer arranged on the lateral surfacesof the LED chip and/or the phosphor body. A first group of the lightemitting devices is arranged in a first linear array having first gaps,and a first optical system is arranged near the first group of lightemitting devices. An optical axis of the first optical system issubstantially orthogonal to the first linear array. At least one secondgroup of the light emitting devices is arranged in at least one secondlinear array parallel to the first linear array, having second gaps, atleast one second optical system is arranged near the at least one secondgroup of light emitting devices, an optical axis of the second opticalsystem being substantially orthogonal to the second linear array, andthe first and at least one second optical systems are arranged so that,in a predetermined distance from the illumination device, light emittedby the first group of light emitting devices, collimated by the firstoptical system, and light emitted by the at least one second group oflight emitting devices, collimated by the at least one second opticalsystem, superimpose to form a substantially gap-free illumination field.

Instead of using a complicated optical system for reducing the gaps inthe illumination field, the inventive illumination device uses twooptical systems, each providing a partial illumination field with gapsdue to the gaps between LED light source devices in the respectivearrays. The partial illumination fields superimpose so that the lightbeams of one partial illumination field meet the gaps of the otherpartial illumination field, and vice versa. The resulting illuminationfield can be substantially gap-free.

While reference is made to the resulting illumination field beingsubstantially gap-free at the predetermined distance, it is understoodthat the resulting illumination field preferably remains substantiallygap-free at distances greater than the predetermined distance.

Each of the LED light source devices may have a light emitting surfacewith a predetermined first width in the direction of the first or secondarray. Each of the gaps between neighboring LED light source devices mayhave a predetermined second width in the direction of the first orsecond array. The first and second width may be selected so that thedistance between the light emitting surfaces of neighboring LED lightsource devices substantially equal an integer multiple of the firstwidth. The distance between the light emitting surfaces of neighboringLED light source devices may substantially equal the first width.

In at least one variant, the optical axes of the first and secondoptical system may be substantially parallel to each other. The positionof the light source devices of the second group of light source devicesrelative to the optical axis of the second optical system may be offsetwith respect to the position of the light source devices of the firstgroup of light source devices relative to the optical axis of the firstoptical system.

In another variant, the first and second arrays may be arranged along abase line parallel to the first and second arrays. The first and secondarrays may be arranged along a base line orthogonal to the first andsecond arrays.

In another variant, the first width may between 0.5 mm and 1 mm.

In another variant, the first and second optical systems may includepositive lenses. The first and second arrays may be substantiallyarranged in the focus planes of respective positive lenses.

In another variant, the first and second groups of light emittingdevices may be placed on first and second printed circuit boards. Thefirst and second groups of light emitting devices may be placed on acommon printed circuit board.

In another variant, the illumination device may further include acontrol unit capable of selectively activating/deactivating individuallight emitting devices of the plurality of light emitting devices.

In another variant, the illumination device may be a vehicle headlight,and the predetermined distance from the illumination device may bebetween 20 m and 30 m, preferably 25 m. The illumination device may be astreetlight, and the predetermined distance from the illumination devicemay be between 3 m and 6 m. The illumination device may be a room light,and the predetermined distance from the illumination device may bebetween 2 m and 4 m.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an LED light source device according to one or moreembodiments of the present disclosure.

FIG. 2 illustrates an illumination device including the LED light sourcedevice shown in FIG. 1 .

FIG. 3 illustrates an array of light emitting devices.

FIG. 4 illustrates a light field emitted by the illumination device ofFIG. 2 .

FIG. 5A illustrates an improved illumination device including a firstgroup of LED light source devices arranged in a first array.

FIG. 5B illustrates the improved illumination device including a secondgroup of LED light source devices arranged in a second array.

FIGS. 6A to 6C illustrate a light field emitted by the illuminationdevice of FIG. 5 , where:

FIG. 6A illustrates a light field emitted by a first array of theillumination device;

FIG. 6B illustrates a light field emitted by a second array of theillumination device; and

FIG. 6C illustrates a light field emitted by the first array and thesecond array of the illumination device.

FIGS. 7A to 7C illustrates printed circuit boards, where:

FIG. 7A illustrates at least two arrays of the illumination deviceplaced on separate circuit boards;

FIG. 7B illustrates at least two arrays of the illumination deviceplaced on a common circuit board; and

FIG. 7C illustrates another arrangement of the illumination device on acircuit board.

FIGS. 8A and 8B illustrate two-dimensional arrays of LED light emittingdevices, where:

FIG. 8A illustrates a combination of two arrays where each arrayincludes two rows of the LED light source devices in a firstarrangement; and

FIG. 8B illustrates that light of respective LED light source devicesmerges into a seamless light field having two rows of light beams.

FIGS. 9A and 9B illustrate two-dimensional arrays of LED light emittingdevices, where:

FIG. 9A illustrates a combination of two arrays where each arrayincludes three rows of LED devices in a second arrangement; and

FIG. 9B illustrates that light of respective LED light source devicesmerges into a seamless light field having three rows of light beams.

FIGS. 10A and 10B illustrate two-dimensional arrays of LED lightemitting devices, where:

FIG. 10A illustrates a combination of two arrays where each arrayincludes four rows of LED devices in a third arrangement; and

FIG. 10B illustrates that light of respective LED light source devicesmerges into a seamless light field having four rows of light beams.

FIG. 11 illustrates another embodiment of an illumination deviceaccording to the present disclosure.

DETAILED DESCRIPTION

Possible embodiments of the invention will now be described in detailwith reference to exemplary drawings. The drawings and the embodimentsdescribed hereafter only serve for better understanding of theinvention, without limiting the scope of the invention to the exactdetails of the described embodiments. The scope of the invention is tobe determined by the appended claims.

FIG. 1 shows a cross-sectional view of an LED light source device 1. TheLED light source device 1 includes an LED chip 2 connected to a firstlead frame 3 with an anode side of the LED chip 2. A cathode side of theLED chip 2 is connected to a second lead frame 4. In other forms, thelead frames 3 and 4 may be omitted, and solder contacts may be directlyprovided on a surface of the LED chip.

The LED chip 2 is embedded in a phosphor body 6. The phosphor body 6serves to convert narrow-band-width light emitted by the LED chip 2 intoillumination light of a desired color temperature. The phosphor body 6can also serve to mechanically connect first and second lead frames 3and 4.

In some forms, the phosphor body 6 can include a transparent resin withimmersed phosphor particles (not shown). The immersed phosphor particlescan include one or more different types of phosphor, and are selected toprovide a desired color temperature of the illumination light.

The lateral sides of the phosphor body 6 are surrounded by a lightblocking layer, also referred to as reflector layer 7, as shown in FIG.1 . The reflector layer 7 is provided so that excitation light and/orillumination light do not exit the LED light source device 1 at thelateral sides thereof and enter into neighboring LED light sourcedevices. Such cross-illumination may reduce available contrast of anillumination device using the LED light source devices, which isundesirable.

The reflector layer 7 may include silicon with embedded TiO₂ particles.It is sometimes also referred to as side coating.

Due to the above-described structure of LED light source devices, theLED light source devices include a light emitting surface portionsurrounded by a surface which does not emit light. Only by way ofexample, the light emitting surface portion has a size of about 1 mm² orless, for example between 0.5 mm² and 1 mm². The reflector layer 7 mayhave a thickness of about 0.01 mm or less.

FIG. 2 depicts an illumination device 10 including a plurality of LEDlight source devices 1 arranged on a circuit board 11 in a linear array12. A lens 15 is provided for collimating the light emitted by theindividual LED light source devices 1. Therefore, the light emittingsurface portions of the LED light source devices 1 are approximatelyplaced in focal plane of the lens 15. While the lens 15 is depicted as asingle lens, the present disclosure is not limited thereto and aplurality of lenses may form an optical system. Such an optical systemmay e.g., provide for color correction of the illumination light, lengthand/or weight reduction of the optical system, or both. The opticalsystem may include reflective elements instead of or in addition tolenses.

FIG. 3 depicts an array 12 of LED light source devices 1 in a plan view.The individual LED light source devices 1 are positioned to leave gaps20 between neighboring LED light source devices 1. The gaps 20 arearranged for several reasons.

One reason is that it is difficult to place the LED light sources 1without gaps 20 in an automated process, as each automated process maybe configured to provide for positional tolerances. Another reason isthat the gaps 20 provide for dissipation of heat created in theindividual LED light source devices 1. A further reason may be that leadframes of neighboring LED light source devices are configured to have aminimum distance to avoid short-circuits.

As a consequence, the light emitting surface portions of neighboring LEDlight source devices 1 in the array 12 are separated by a distance “d”,which is equal to the width of a gap 20 plus double width of a reflectorlayer 7. The double width of the reflector layer 7 includes a width ofthe reflector layer 7 of one LED light source device 1 and a width ofthe reflector layer 7 of a neighboring LED light source device thereof.

A possible light field emitted by the illumination device of FIG. 2 isdepicted in FIG. 4 . The light field is defined by the projection of thelight emitted by individual LED light source devices 1 through the lens15 onto a reference plane 35 having X-axis and Y-axis. For automotiveapplications, the reference plane may be 25 meters away from theillumination device.

It can be seen that the light field includes several light beams 30separated by dark spaces 31. The dark spaces 31 can be seen asprojections of the gaps 20 and the reflector layers 7, which separatethe light emitting surface portions of the LED light source devices 1.

In some forms, the lens 15 may be modified so that the dark spaces 31are reduced. Such modifications may come with increased cost of the lens15, although available contrast of the illumination device 10 may bemaintained.

FIGS. 5A and 5B illustrate one embodiment of an illumination device 100according to the present disclosure. FIG. 5A illustrates that theillumination device 100 includes a first group of LED light sourcedevices 101 arranged in a first array 102. FIG. 5B illustrates that theillumination device 100 includes a second group of LED light sourcedevices 111 arranged in a second array 112.

As shown in FIGS. 5A-5B, the first group of LED light source devices 101is arranged in the first array 102, and individual LED light sourcedevices 101 are separated from neighboring LED light source devices 101by gaps 103. A first lens 105 is positioned near the first array 102 ofLED light source devices, so that an optical axis 106 of the first lens105 is approximately orthogonal to the first array 102, and the lightemitting surfaces of the first group of LED light source devices 101 arepositioned approximately on a focal plane of the first lens 105.

The first lens 105 can be a single lens or an optical system includingmore than one optical elements, as described above with reference toFIG. 2 .

The second group of LED light source devices 111 is arranged in thesecond array 112 located adjacent to the first array 102. As shown inFIGS. 7A and 7B, the first array 102 and the second array 112 arepositioned side by side on two separate circuit boards, or on the samecircuit board.

In the second array 112, individual LED light source devices 111 areseparated by gaps 113. A second lens 115 is positioned so that anoptical axis 116 of the second lens 115 is approximately orthogonal tothe second array 112, and the light emitting surfaces of the LED lightsource devices 111 are positioned approximately on a focal plane of thesecond lens 115.

The light field emitted by the first array 102 of LED light sourcedevices 101 is depicted in FIG. 6A. The light field emitted by thesecond array 112 of LED light source devices 111 is depicted in FIG. 6B.FIGS. 6A to 6C show projection plane, having X-axis and Y-axis, on whichlight beams emitted by the individual LED light source devices.

It can be seen that, similar to the light field depicted in FIG. 4 , thelight fields depicted in FIGS. 6A and 6B include light beams 120 and121, corresponding to the light emitting surface portions of LED lightsource devices 101 and 111, separated by dark spaces 122 and 123. Thedark spaces 122 and 123 correspond to the gaps 103 and 113 of the firstand second arrays 102 and 112 and the non-light-emitting surfaceportions of the LED light source devices 101 and 111.

The gaps 103 of the first array 102 are dimensioned so that the lightbeams 120 of the light field emitted by the first array 102 fit in thedark spaces 122 of the light field emitted by the first array 102. Thegaps 113 of the second array 112 are dimensioned so that the light beams121 of the light field emitted by the second array 112 fit in the darkspaces 123 of the light field emitted by the second array 112.Therefore, the gaps 103 and 113 of the first and second arrays 102 and112 are dimensioned so that the distance d between the light emittingsurface portions of neighboring LED light source 101 and 111 devicesequals to the width of the lights emitting surface portions of the LEDlight source devices 101 and 111. At the same time, the positions of theLED light source devices 101 in the first array 101 with respect to thefirst optical axis 106 are offset by about half the width of the lightemitting surface portions, in light of the positions of the LED lightsource devices 111 with respect to the second optical axis 116.

The first and second arrays 102 and 112 and the first and second lenses105 and 115 are positioned so that in an area of interest, the lightfields emitted by the first and second arrays 102 and 112 overlap toform a continuous and seamless light field, which is depicted in FIG.6C. The area of interest may include the predetermined distance andextend beyond the predetermined distance. In automotive application,where the predetermined distance may be 25 m according to photometricregulations, the area of interest may e.g., extend up to 100 m, up to150 m, or even beyond that.

If the area of interest is very far away from the first and secondlenses 105 and 115, the optical axes 106 and 116 can be approximately inparallel to each other. In other embodiments, the first and secondoptical axes 106 and 116 may form a sharp angle.

In the example depicted in FIGS. 5A and 5B, the illumination device 100includes two arrays 102 and 112 of LED light source devices 101 and 111.Alternatively, the illumination device 100 may include more than twoarrays of LED light source devices, and the gaps between neighboring LEDlight source devices may be dimensioned so that the distance between thelight emitting surface portions of neighboring LED light source devicesis equal to an integer multiple of the width of the light emittingsurface portions.

The at least two arrays of LED light source devices may be placed onseparate circuit boards, as depicted in FIG. 7A. The first array 102 ofLED light source devices 101 is placed on a first circuit board 150 andcan be connected by first connection wires 151. The second array 112 ofLED light source devices 111 is placed on a second circuit board 160 andcan be connected by second connection wires 161.

Placing the at least two arrays of LED light source devices on separatecircuit boards facilitates easy adjustment of the relative positions ofrespective arrays.

The at least two arrays of LED light source devices may instead beplaced on a common single circuit board, as depicted in FIG. 7B. Here,the first array 102 of LED light source devices 101 and the second array112 of LED light source devices 111 are placed side by side on a singlecircuit board 170, connectable by connection wires 171.

Placing the at least two arrays of LED light source devices on a commoncircuit board facilitates easy handling of the respective arrays duringmanufacturing of the illumination device.

In the FIGS. 7A and 7B, the first and second arrays 102 and 112 arearranged along a base line (not shown) which is parallel to the firstand second arrays 102 and 112.

FIG. 7C depicts another arrangement of LED light source devices on acircuit board 180. Here, the first array 102 of LED light source devices101 and the second array 112 of LED light source devices 111 arearranged along a base line (not shown) which is orthogonal to therespective arrays 102 and 112. In this case, the optical axes 106 and116 of the lenses 105 and 115 (not shown) can be moved very close toeach other. To avoid mechanical interference of the lenses, overlappingportions of the lenses may be cut away without significantly affectingoptical performance. As an alternative to cutting lenses, a plurality ofmicro lenses may be used, each micro-lens collimating light emitted by asingle LED light source device, or by a small group of LED light sourcedevices.

In the above-described embodiments, the placement of individual LEDlight source devices in arrays with significant gaps leaves sufficientspace for placing conductive connection structures for contacting theindividual LED light source devices, and/or for placing heat managementfeatures like heat sinks, heat pipes or the like. Therefore, the overallperformance and lifetime of illumination devices can greatly improve.While the previous examples disclose one-dimensional arrays of LED lightsource devices, two-dimensional arrays of LED light source devices canbe employed to provide enhanced space resolution of an illuminationdevice. Some examples of two-dimensional arrays are depicted in FIGS. 8Aand 8B through FIGS. 10A and 10B. Embodiments of illumination devicesshown in FIGS. 8A through 10B provide substantially gap-freeillumination fields by arranging two or more arrays having a partialillumination field with gaps in various patterns and/or manners. Basedon various arrangements, the partial illumination fields aresuperimposed so that the light beams of one partial illumination fieldmeet the gaps of the other partial illumination field, and vice versa.The resulting illumination field can be substantially gap-free. The twoor more arrays are associated and arranged with respective opticalsystems so that, in a predetermined distance from the illuminationdevice, light emitted by a first group of light emitting devices,collimated by a first optical system, and light emitted by a secondgroup of light emitting devices, collimated by a second optical system,are superimposed to form a gap-free illumination field.

FIG. 8A depicts a combination of two arrays 201 and 202, where eacharray includes two rows of LED light emitting devices 203 in a firstarrangement. FIG. 8B illustrates that the light of the respective LEDlight source devices 203 merges into a seamless light field having tworows of light beams.

FIG. 9A depicts a combination of two arrays 211 and 212, where eachincludes three rows of LED light emitting devices 213 in a secondarrangement. FIG. 9B illustrates that the light of the respective LEDlight source devices 213 merges into a seamless light field having threerows of light beams.

FIG. 10A depicts a combination of two arrays 221 and 222, where eachincludes four rows of LED light emitting devices 223 in a thirdarrangement. FIG. 10B illustrates that the light of the respective LEDlight source devices 223 merges into a seamless light field having fourrows of light beams.

Instead of using a complicated optical system for reducing the gaps inthe illumination field, the embodiments shown in FIGS. 8A, 9A and 10Ause two optical systems, where each array or row of LED light emittingdevices provides a partial illumination field with gaps. The partialillumination fields are superimposed so that the light beams of onepartial illumination field meet the gaps of the other partialillumination field, and vice versa. The resulting illumination field canbe substantially gap-free in a distance from the illumination device.

FIG. 11 depicts a further example of an illumination device including afirst group of LED light source devices 101 arranged in a first array102, at least one second group of LED light source devices 111 arrangedin at least one second array 112, and a control device 300, configuredfor selectively activating, controlling, and/or deactivating individualLED light source devices 101 and 111.

Individual control of LED light source devices may be facilitated byindividually providing a supply voltage to each LED light source device,while all LED light source devices are connected to a common groundconductor. Alternatively, all LED light source devices may be connectedto a common supply voltage, and the driving current of each LED lightsource device may individually be controlled.

The illumination device shown in FIG. 11 enables selective control ofbrightness in individual sections of a light field corresponding toindividual LED light source devices, which can be beneficial for severalpurposes.

In some embodiments, an illumination device according to this disclosuremay be used as a vehicle headlight. In such application to the vehicleheadlight, brightness control of individual sections of the light fieldmay be used to avoid blinding of upcoming traffic or pedestrians, whileproviding optimal illumination of the driver's field of view. Instead ofa driver's field of view, the headlights can be used to illuminate thefield of view of machine vision systems in autonomous ormachine-assisted driving vehicles.

Illumination devices according to this disclosure can be applied for anadaptive driving beam of a vehicle. Additionally, illumination devicesaccording to the present disclosure may equally be applied for high-beamor low-beam illumination.

In a further possible application, an illumination device according tothis disclosure may be used as a road light. In such application,brightness control of individual sectors of the light field may be usedto provide adaptive brightness for different parts of the road likedriveway and sidewalk parts.

In a different application, an illumination device according to thisdisclosure may be used as a room light. Brightness control may be usedto provide customized illumination according to the preferences of auser.

The examples of the present disclosure have been described above asspecific embodiments, but these are only examples, and the presentdisclosure is not limited thereto, and should be construed as having thewidest scope according to the technical spirit disclosed in the presentspecification. A person skilled in the art may combine/substitute thedisclosed embodiments to implement a pattern of a shape that is notdisclosed, but it also does not depart from the scope of the presentdisclosure. In addition, those skilled in the art can easily change ormodify the disclosed embodiments based on the present specification, andit is clear that such changes or modifications also belong to the scopeof the present disclosure.

1. An illumination device, including: a LED module; and an opticalsystem arranged in proximity to the LED module and configured tocollimate light emitted by the LED module, wherein the LED moduleincludes: a plurality of light sources for emitting excitation light; aplurality of phosphors covering each of the plurality of light sourcesand configured to convert the excitation light into illumination light;and a light blocking layer arranged on lateral surfaces of the pluralityof phosphors; wherein: a first group of the light sources is arranged ina first linear array having first gaps between the light sources, asecond group of the light sources is arranged in a second linear arrayparallel to the first linear array and having second gaps between thelight sources, each of the plurality of phosphors has a light emittingsurface having a size of 1 mm² or less, and at least one of the lightsources in the first group is controlled separately from at least one ofthe light sources in the second group.
 2. The illumination device ofclaim 1, wherein the light sources in the first group are disposed alonga first direction and the second linear array is disposed from the firstlinear array along a second direction perpendicular to the firstdirection.
 3. The illumination device of claim 2, wherein the lightsources in the second group are disposed along the first direction. 4.The illumination device of claim 1, wherein the plurality of phosphorsincludes transparent resin with phosphor particles.
 5. The illuminationdevice of claim 1, wherein the first linear array and the seco nd lineararray are arranged side by side along a base line.
 6. The illuminationdevice of claim 1, wherein the optical system comprises a lens, and thefirst linear array and the second linear array are substantiallyarranged on focus planes of the lens.
 7. The illumination device ofclaim 1, wherein the optical system comprises a first optical systemincluding a first lens and a second optical system including a secondlens, the first optical system and the second optical system disposedapart from each other.
 8. An illumination device, including: a LEDmodule; and an optical system for collimating light emitted by the LEDmodule, wherein the LED module includes: a plurality of light sourcesfor emitting excitation light; a plurality of phosphors covering each ofthe plurality of light sources and configured to convert the excitationlight into illumination light; and a light blocking layer arranged onlateral surfaces of the plurality of phosphors; wherein: a first groupof the light sources is arranged in a first linear array having firstgaps between the light sources, a second group of the light sources isarranged in a second linear array parallel to the first linear array andhaving second gaps between the light sources, each of the plurality ofphosphors has a light emitting surface and a number of light emittingsurfaces covering the light sources in the first group is greater than anumber of light emitting surfaces covering the light sources in thesecond group, at least one of the light sources in the first group andat least one of the light sources in the second group are controlledseparately from each other.
 9. The illumination device of claim 8,wherein the optical system comprises a first optical system including afirst lens and a second optical system including a second lens, thefirst optical system and the second optical system disposed apart fromeach other.
 10. The illumination device of claim 8, wherein the lightsources in the first group are disposed along a first direction and thesecond linear array is disposed from the first linear array along asecond direction perpendicular to the first direction.
 11. Theillumination device of claim 10, wherein the light sources in the secondgroup are disposed along the first direction.
 12. The illuminationdevice of claim 8, wherein the first group of light emitting devices isplaced on a first circuit board, and the second group of light emittingdevices is placed on a second circuit board.
 13. The illumination deviceof claim 8, wherein regions of light emitted by the light sources in thefirst group and the light sources in the second group overlap to form acontinuous light field.
 14. An illumination device, including: a LEDmodule; and an optical system arranged in proximity to the LED moduleand configured to collimate light emitted by the LED module, wherein theLED module includes: a plurality of light sources for emittingexcitation light; a plurality of phosphors covering each of theplurality of light sources for converting the excitation light intoillumination light; and a light blocking layer arranged on lateralsurfaces of the plurality of phosphors; wherein: a first group of thelight sources is arranged in a first linear array having first gapsbetween the light sources, a second group of the light sources isarranged in a second linear array parallel to the first linear array andhaving second gaps between the light sources, a region of the lightblocking layer overlapping with at least one of a first gap or a secondgap is about 0.01 mm or less, and at least one of the light sources inthe first group and at least one of the light sources in the secondgroup are controlled separately from each other.
 15. The illuminationdevice of claim 14, wherein each of the plurality of phosphors has alight emitting surface and a number of light emitting surfaces coveringthe light sources in the first group is greater than a number of lightemitting surfaces covering the light sources in the second group. 16.The illumination device of claim 14, each of the plurality of phosphorshas a light emitting surface having a size of 1 mm² or less.
 17. Theillumination device of claim 14, wherein the optical system comprises: afirst optical system arranged in proximity to the first group of lightsources and having an optical axis being substantially orthogonal to thefirst linear array; and a second optical system arranged in proximity tothe second group of light sources and having an optical axis beingsubstantially orthogonal to the second linear array; and
 18. Theillumination device of claim 17, wherein the optical axis of the firstoptical system and the optical axis of the second optical system aresubstantially parallel to each other.
 19. The illumination device ofclaim 14, wherein the light sources in the first group are disposedalong a first direction and the second linear array is disposed from thefirst linear array along a second direction perpendicular to the firstdirection.
 20. The illumination device of claim 19, wherein the lightsources in the second group are disposed along the first direction.